EDTA/ Disodium EDTA - buffer prep question (Sep/15/2008 )

Hi,

I am trying to make a buffer where one of the components is 1mM EDTA. I have a bottle of Disodium EDTA, but as EDTA and Disodium EDTA have diferent molecular weights, I can't be sure if I need the disodium salt or the acid. Any advice would be very welcome.

Thanks,

Shurjo

-RNAjock-

is ionic strength absolutely important to your solution?

What pH is your solution?

In most situations the ionic strength of the solution is not absolutely vital, so stock solutions of the disodium salt of EDTA would be used. The disodium salt is more soluble, and thus the stock solution easier to prepare.

But if ionic strength is absolutely important, and the solution you are making has an acidic pH, I would use the acid form of EDTA.